The Zodiac Killer was never caught, but he may have been identified at last, news outlets reported Wednesday. The murderer grew to infamy after five unsolved murders in the late 1960s. He wrote several letters to police boasting about the slayings, claiming 37 victims, and sent bloody swatches of clothing to authorities to verify his assertions.

The Zodiac Killer has been one of the greatest unsolved crime mysteries in the nation, until now: that’s what a Louisiana man has asserted.

Gary L. Stewart set out to discover his father, the man he never knew, but instead uncovered something much more sinister: The man who helped bring him into the world was the same who is believed to have murdered five people in Northern California.

Stewart concluded that his biological father-- Earl Van Best Jr., now dead -- was the Zodiac Killer, CNN wrote. Though Stewart believes he knows the serial killer’s true identity, California police aren’t so sure. More than four decades since the Zodiac Killer terrorized Northern California, authorities still consider the case “open.”

"It's an open and active case, so we don't comment," San Francisco police spokesman Albie Esparza told CNN. "But (it's) certainly something our homicide investigators will take a look at."

Capt. Steve Blower of the Napa County Sheriff's Office added to CNN: "We have talked to many people over the years. We've gotten reports over the years from people who don't pan out. This case is still open, and we still do accept tips or leads that may have bearing on the case."

Stewart’s book, "The Most Dangerous Animal of All: Searching for My Father ... and Finding the Zodiac Killer," was co-written with journalist Susan Mustafa.

"Stewart and Mustafa construct a chilling psychological profile of Stewart's father: as a boy with disturbing fixations, as a frustrated intellectual with pretensions to high culture, and as an inappropriate suitor and then jilted lover unable to process his rage," says their publisher, HarperCollins.

HarperCollins publicist Tina Andreadis told CNN: "Stewart's father had a criminal record in San Francisco [forgeries, bad checks], and there was a strong resemblance between his father's mug shot and the police sketch.”

"If you look at Gary's photo next to the sketch of the Zodiac, next to his father's mugshot, you can see that there is very clearly more than just a passing resemblance," Andreadis said. "They look alike."

Though it might seem Stewart is just looking for notoriety, he told People magazine “This is the last thing I wanted to find out, believe me.”

Stewart, the 51-year-old owner of a Baton Rouge-based industrial cleaning company, conducted 12 years of research where he consulted with handwriting specialists, forensic scientists and more than 500 people, he says in his book that was released on Tuesday.

Why would someone want to know his father was a cold-blooded killer? Stewart told People magazine he wanted to “bring some closure to the families of my father's victims.” He unsuccessfully tried to get the San Francisco police to compare his DNA to the Zodiac Killer’s, he details in his book.

Stewart was adopted and didn’t find out about his birth parents until his biological mother reached out to him in 2002. He discovered his mother, Judith Gilford, was 14 when she ran away from home with a 27-year-old rare book dealer named Earl Van Best Jr. She told her son Best forced her to abandon the baby since the police were searching for her, a minor.

"I still don't have all the answers,” Stewart said. "I never will. But I've got all the answers I want and I’m truly ready to get on with my life."

It should be noted. as Gawker reported in 2010, that this is not the first time someone has claimed their father was the Zodiac Killer.

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